[LEC] Unit 6: Opportunistic Mycoses Flashcards
Infections in patients with immune deficiencies who would otherwise not be infected
Opportunistic mycoses
Endogenous/Exogenous: Part of a normal human flora (microbiota)
Endogenous
Endogenous/Exogenous: Fungus does not normally live in/on human body
Exogenous
Examples of Endogenous fungi
Candida spp.
Pneumocystis jirovecii
Examples of Exogenous fungi
Cryptococcus neoformans
Aspergillus spp.
Zygomycetes
Condition caused by Candida albicans
Candidiasis or Moniliasis
Causes the most frequent opportunistic fungal infections
Candida spp.
Harmless inhabitants of the skin and mucous membranes (RT, GIT, Female Genital tract)
Candida spp.
T or F: Normal immune system keeps Candida off body surfaces
F
keeps Candida on
Examples of other candida spp.:
○ C. tropicalis
○ C. krusei
○ C. parapsilosis
○ C. glabrata
○ C. gullermondii
○ C. lusitaniae
○ C. kefyr
T or F: CD4 is a main defense mechanism of the body against Candida
T
The most important risk factor in Candidiasis
Neutropenia
Onychomycosis is the infection of what body part?
Nails
T or F: Only about 30% of candidemia cases can be proven
F
50%
T or F: The mortality of candidemia is 30-40%
T
Identify the colors seen in Chrom Agar:
● C. albicans-
● Candida krusei-
● Candida tropicalis-
● Other species-
● C. albicans- green
● Candida krusei- pink
● Candida tropicalis- metallic blue
● Other species- white to mauve
Alternative for Chrom Agar
Germ Tube
T or F: C. albicans is germ tube (+) in low protein environment
F
high protein
Candida spp. that are (+) in Germ Tube Test
C. albicans and C. dubliniensis
Example of high protein environment for Germ Tube Test
Plasma / Serum
T or F: Cross infections of candidiasis are common among ICU patients
T
Treatment of Candidiasis
Amphotericin B (for neutropenic patients)
Fluconazole (nonneutropenic patients)
Nystatin (suppresses intestinal and vaginal candidiasis)
Caspofungin
Causative agent of Pneumocystis Pneumonia
Pneumocystis jirovecii
T or F: Pneumocystis jirovecii was previously classified as a bacteria
F
protozoa
Present in lungs of many mammals, including humans, in persistent but harmless infection
Pneumocystis jirovecii
Patients who underwent transplantation are given __________ _______ so that the body will not reject the organ
immunosuppressive agents
T or F: Corticosteroid can weaken the immune system
T
Causes interstitial pneumonitis in compromised patients
P. jirovecii
Treatment and prevention of P. jirovecii
Co-trimoxazole
Pentamidine
Condition caused by Cryptococcus neoformans
Cryptococcosis or Torulosis
Occurs worldwide in soil and in bird droppings
C. neoformans
Prominent feature: thick polysaccharide capsule, which causes evasion from phagocytosis
C. neoformans
T or F: C. neoformans may disseminate in other organs like the brain, causing meningitis
T
T or F: Exudate can be used as a specimen for C. neoformans
T
Treatment of C. neoformans
Combination of chemotherapy of Amphotericin B and Flucytosine
Infection is always exogenous, it is not transmitted from human to human
C. neoformans
Test for C. neoformans that detects enzyme phenol oxidase
Niger Seed Agar
Causative agent of Aspergillosis
Aspergillus spp.
Aspergilli are worldwide occurring _________,
living in soil and on plants; they have small conidia that form aerosols
saprophytes
Produce aflatoxins in food
Aspergillus flavus
Color of Aspergillus colonies on SDA
gray to green
Treatment for Aspergillosis
Amphotericin B, Itraconazole, Flucytosine and Surgery
T or F: Aspergillosis can be prevented by avoiding exposure to conidia (new buildings)
T
Causative agents of Zygomycosis
Mucor
Rhizopus
Absidia
Rhizomucor
It is an invasive disease caused by zygomycetes
Zygomycosis
These fungi are ubiquitous thermotolerant saprophyte; spores are present in air and dust
Zygomycosis
It is an obsolete polyphyletic taxon
Class Phycomycetes
T or F: Spores of Rhizopus remain adhered to the columella thus not easily disseminated
F
should be Mucor
Have globose sporangia
and sporangiophores are
not swollen where they
merge with the columellae
Absidia
Results from germination of the sporangiospores in the nasal passages and invasion of the hyphae into the blood vessels, causing thrombosis, infarction
and necrosis
Rhinocerebral mucormysosis
This follows inhalation of the sporangiospores with
invasion of the lung parenchyma and vasculature
Thoracic mucormysosis
